Module: Multi Direction Lee Filter
Copyrights (c) 2003 by Andre Ringeler
Menu: Grid > Filter
Description
This Multi Direction Lee Filter is a enhanced Lee Filter
It looks into 16 directions for the direction with the minium variance
and applied a Lee Filter on this direction.

Uses this filter for remove speckle noise in SAR images or DTMs.
On DTMs this filter will preserves the slope and narrow valleys.

For details on the Lee Filter, see the article by Jong-Sen Lee:
"Digital Image Enhancement and Noise Filtering by Use of Local Statistics",
IEEE Transactions on Pattern Analysis and Machine Intelligence,
Volume PAMI-2, Number 2, pages 165-168, March 1980.


Parameters
NameTypeIdentifierDescriptionConstraints
Input
Grid Grid (input)INPUT
Output
Filtered GridGrid (output)RESULT
Direction (*)Grid (optional output)DIRDirection of the filter with minimum variance.
Minimum Variance (*)Grid (optional output)VAR
Options
Noise VarianceFloating pointNOISE
(*) optional